Comma in English | Easy Explanation with Examples | Punctuation Marks

Appositives add extra information about a noun, and when that information is not essential, it should be set off with commas. Example: My brother, a firefighter, lives in Texas. The appositive “a firefighter” gives us extra information about “my brother,” but the sentence still makes sense without it. That’s why we use commas. However: Author Alan Gratz wrote Refugee. Here, “Alan Gratz” identifies which author, so no commas are needed. Learning when to use appositives can make your writing clear